N. van der Maas, J. Dijs-Elsinga, J. Kemmeren, A. van Lier, M. Knol, H. de Melker During the H1N1 pandemic there was a high use of maternal vaccination against influenza in the Netherlands. Multivariate analyses of data of 1357 vaccinated women and 669 non-vaccinated women showed no association between vaccination and subsequent small-for-gestational-age or prematurity. Normal head circumference and developmental scores suggested no deleterious effects of maternal vaccination on the brain. There were no differences in medical contacts suggesting no general health effects of maternal vaccination. In summary, this large study did not find any evidence of safety issues of maternal vaccination against influenza in the Netherlands.